mdev34041-cleanups.diff

diff --git a/sql/item_subselect.cc b/sql/item_subselect.cc
index 52fcbf96018..00dede9bc7d 100644
--- a/sql/item_subselect.cc
+++ b/sql/item_subselect.cc
@@ -5029,7 +5029,7 @@ subselect_hash_sj_engine::choose_partial_match_strategy(
       strategy= PARTIAL_MATCH_SCAN;
     else
       item->get_IN_subquery()->get_materialization_tracker()->
-          set_partial_match_buffer_size(pm_buff_size);
+          report_partial_match_buffer_size(pm_buff_size);
   }
 }
 
@@ -5805,7 +5805,7 @@ int subselect_hash_sj_engine::exec()
     }
   }
 
-  item_in->get_materialization_tracker()->set_exec_strategy(strategy);
+  item_in->get_materialization_tracker()->report_exec_strategy(strategy);
   if (pm_engine)
     lookup_engine= pm_engine;
   item_in->change_engine(lookup_engine);
@@ -6292,7 +6292,7 @@ int subselect_partial_match_engine::exec()
     else
     {
       /* Search for a complete match. */
-      tracker->increment_index_lookup_loops();
+      tracker->increment_index_lookups();
       if ((lookup_res= lookup_engine->index_lookup()))
       {
         /* An error occurred during lookup(). */
@@ -6545,7 +6545,7 @@ subselect_rowid_merge_engine::init(MY_BITMAP *non_null_key_parts,
     return TRUE;
 
   item->get_IN_subquery()->get_materialization_tracker()->
-      track_partial_merge_keys(merge_keys, merge_keys_count);
+      report_partial_merge_keys(merge_keys, merge_keys_count);
   return FALSE;
 }
 
@@ -7004,7 +7004,7 @@ void Item_subselect::init_expr_cache_tracker(THD *thd)
 }
 
 
-void Subq_materialization_tracker::track_partial_merge_keys(
+void Subq_materialization_tracker::report_partial_merge_keys(
     Ordered_key **merge_keys, uint merge_keys_count)
 {
   partial_match_array_sizes.resize(merge_keys_count, 0);
diff --git a/sql/item_subselect.h b/sql/item_subselect.h
index 4a5c50fd71d..47aa0ffffcf 100644
--- a/sql/item_subselect.h
+++ b/sql/item_subselect.h
@@ -1580,108 +1580,71 @@ class Subq_materialization_tracker
       partial_matches_count(0)
   {}
 
-  void track_partial_merge_keys(Ordered_key **merge_keys,
-                                uint merge_keys_count);
+  void report_partial_merge_keys(Ordered_key **merge_keys,
+                                 uint merge_keys_count);
 
-  const char *get_exec_strategy() const
-  {
-    switch (exec_strategy)
-    {
-      case Strategy::UNDEFINED:
-        return "undefined";
-      case Strategy::COMPLETE_MATCH:
-        return "index_lookup";
-      case Strategy::PARTIAL_MATCH_MERGE:
-        return "index_lookup;array merge for partial match";
-      case Strategy::PARTIAL_MATCH_SCAN:
-        return "index_lookup;full scan for partial match";
-      default:
-        return "unsupported";
-    }
-  }
-
-  void set_exec_strategy(Strategy es)
+  void report_exec_strategy(Strategy es)
   {
     exec_strategy= es;
   }
 
-  bool has_partial_match_buffer_size() const
-  {
-    return partial_match_buffer_size != 0;
-  }
-
-  ulonglong get_partial_match_buffer_size() const
-  {
-    return partial_match_buffer_size;
-  }
-
-  void set_partial_match_buffer_size(longlong sz)
+  void report_partial_match_buffer_size(longlong sz)
   {
     partial_match_buffer_size= sz;
   }
 
-  size_t get_partial_match_arrays_count() const
-  {
-    return partial_match_array_sizes.elements();
-  }
-
-  ha_rows get_partial_match_array_size(size_t idx) const
-  {
-    return partial_match_array_sizes[idx];
-  }
-
   void increment_loops_count()
   {
     loops_count++;
   }
 
-  bool has_loops_count()
-  {
-    return loops_count != 0;
-  }
-
-  ulonglong get_loops_count() const
-  {
-    return loops_count;
-  }
-
-  void increment_index_lookup_loops()
+  void increment_index_lookups()
   {
     index_lookups_count++;
   }
 
-  bool has_index_lookup_loops()
-  {
-    return index_lookups_count != 0;
-  }
-
-  ulonglong get_index_lookup_loops_count() const
-  {
-    return index_lookups_count;
-  }
-
   void increment_partial_matches()
   {
     partial_matches_count++;
   }
-
-  bool has_partial_matches()
-  {
-    return partial_matches_count != 0;
-  }
-
-  ulonglong get_partial_matches_count() const
-  {
-    return partial_matches_count;
-  }
-
+  
+  void print_json_members(Json_writer *writer) const;
 private:
   Strategy exec_strategy;
   ulonglong partial_match_buffer_size;
   Dynamic_array<ha_rows> partial_match_array_sizes;
+
+  /* Number of times subquery predicate was evaluated */
   ulonglong loops_count;
+
+  /* 
+    Number of times we made a lookup in the materialized temptable
+    (we do this when all parts of left_expr are not NULLs)
+  */
   ulonglong index_lookups_count;
+
+  /*
+    Number of times we had to check for a partial match (either by 
+    scanning the materialized subquery or by doing a merge)
+  */
   ulonglong partial_matches_count;
+
+  const char *get_exec_strategy() const
+  {
+    switch (exec_strategy)
+    {
+      case Strategy::UNDEFINED:
+        return "undefined";
+      case Strategy::COMPLETE_MATCH:
+        return "index_lookup";
+      case Strategy::PARTIAL_MATCH_MERGE:
+        return "index_lookup;array merge for partial match";
+      case Strategy::PARTIAL_MATCH_SCAN:
+        return "index_lookup;full scan for partial match";
+      default:
+        return "unsupported";
+    }
+  }
 };
 
 #endif /* ITEM_SUBSELECT_INCLUDED */
diff --git a/sql/sql_explain.cc b/sql/sql_explain.cc
index 0b4ec367860..bfd73074f76 100644
--- a/sql/sql_explain.cc
+++ b/sql/sql_explain.cc
@@ -2717,33 +2717,34 @@ void Explain_subq_materialization::print_explain_json(Json_writer *writer,
 {
   writer->add_member("materialization").start_object();
   if (is_analyze)
+    tracker.print_json_members(writer);
+}
+
+
+void Subq_materialization_tracker::print_json_members(Json_writer *writer) const
+{
+  writer->add_member("r_strategy").add_str(get_exec_strategy());
+  if (loops_count)
+    writer->add_member("r_loops").add_ull(loops_count);
+
+  if (index_lookups_count)
+    writer->add_member("r_index_lookups").add_ull(index_lookups_count);
+
+  if (partial_matches_count)
+    writer->add_member("r_partial_matches").add_ull(partial_matches_count);
+
+  if (partial_match_buffer_size)
   {
-    writer->add_member("r_strategy").add_str(tracker.get_exec_strategy());
-    if (tracker.has_loops_count())
-    {
-      writer->add_member("r_loops").add_ull(tracker.get_loops_count());
-    }
-    if (tracker.has_index_lookup_loops())
-    {
-      writer->add_member("r_index_lookups").add_ull(
-            tracker.get_index_lookup_loops_count());
-    }
-    if (tracker.has_partial_matches())
-    {
-      writer->add_member("r_partial_matches").add_ull(
-            tracker.get_partial_matches_count());
-    }
-    if (tracker.has_partial_match_buffer_size())
-    {
-      writer->add_member("r_partial_match_buffer_size").add_size(
-            tracker.get_partial_match_buffer_size());
-    }
-    if (tracker.get_partial_match_arrays_count() > 0)
-    {
-      writer->add_member("r_partial_match_array_sizes").start_array();
-      for(size_t i= 0; i < tracker.get_partial_match_arrays_count(); i++)
-        writer->add_ull(tracker.get_partial_match_array_size(i));
-      writer->end_array();
-    }
+    writer->add_member("r_partial_match_buffer_size").
+            add_size(partial_match_buffer_size);
+  }
+
+  if (partial_match_array_sizes.elements())
+  {
+    writer->add_member("r_partial_match_array_sizes").start_array();
+    for(size_t i= 0; i < partial_match_array_sizes.elements(); i++)
+      writer->add_ull(partial_match_array_sizes[i]);
+    writer->end_array();
   }
 }
+
diff --git a/sql/sql_explain.h b/sql/sql_explain.h
index 2c5cbcfb00e..845648eea57 100644
--- a/sql/sql_explain.h
+++ b/sql/sql_explain.h
@@ -117,8 +117,8 @@ class Explain_node : public Sql_alloc
   Expression_cache_tracker* cache_tracker;
 
   /**
-    This member is not NULL if the node explains a materialized subquery.
-    Otherwise it is NULL and not used
+    If not NULL, this node is a SELECT (or UNION) in a materialized
+    IN-subquery.
   */
   Explain_subq_materialization* subq_materialization;
 
@@ -1013,7 +1013,10 @@ class Explain_delete: public Explain_update
 
 
 /*
-  EXPLAIN data structure for subquery materialization
+  EXPLAIN data structure for subquery materialization.
+
+  All decisions are made at execution time so here we just store the tracker
+  that has all the info.
 */
 
 class Explain_subq_materialization : public Sql_alloc